\starttypescript[serif][SiyuanSong]
\definefontsynonym[sysongregular] [file:SourceHanSerifSC-Regular]
\definefontsynonym[sysongbold] [file:SourceHanSerifSC-Bold]
\stoptypescript

\starttypescript[serif][SiyuanSong]
\definefontsynonym[Serif] [sysongregular] [features=default]
\definefontsynonym[SerifBold] [sysongbold] [features=default]
\stoptypescript


\starttypescript[mySong]
\definetypeface[mySong][rm][serif][SiyuanSong][default]
\stoptypescript


% % % =======================================================
\starttext


\usetypescript[mySong]
\setupbodyfont[mySong,12pt]
 
人之初，性本善。性相近，习相远。\\
{\bold 苟不教，性乃迁。教之道，贵以专。\\}
\switchtobodyfont[20pt]
昔孟母，择邻处。子不学，断机杼。


\stoptext